Air-Coupled Broadband Impact-Echo Actuation Using Supersonic Jet Flow

The impact-echo method (IE) is a non-destructive testing method commonly used in civil engineering. We propose a completely new approach for air-coupled actuation based on supersonic jet flow. The impinging jet sound generates continuously high sound pressures with a broad frequency bandwidth. This novel concept of utilising aeroacoustic sound for air-coupled IE was evaluated on two concrete specimens and validated using a classical IE device with physical contact. The results show a high agreement with the expected frequencies. Delaminations are correctly detected in depth and size. This proves the high reliability of air-coupled IE based on supersonic jet flow.

Recommended citation: Air-Coupled Broadband Impact-Echo Actuation Using Supersonic Jet Flow; Christoph Strangfeld, Bjarne Grotelüschen, Benjamin Bühling; In: Journal of Nondestructive Evaluation 43, 45 (2024)
Download Paper